The cooling of a gas turbine engine combustor downstream end portion has always been challenging. As the hot combustion products exit the combustor and approach the first stage of turbine vanes, high static pressure regions are created particularly at the vanes leading edge near the vane platforms. Those high static pressure regions result in the formation of vane bow waves also known as horseshoe vortices. Such horseshoe vortices tend to prevent cooling air from flowing over the vane platform and may even drive the hot combustor gases back toward the combustor end walls, thereby resulting in localized overheating problems.
Accordingly, there is a need to minimize or reduce the horseshoe vortex effect at the leading edge of the turbine vane immediately downstream of the combustor outlet end.